Electromechanical relay



April 22, 1958 E. ALIZON ETAL ELECTROMECHANICAL RELAY Filed March 28, 1955 United States Patent ELECTROMECHANICAL RELAY Etienne Alizon, La Celle St. Cloud, and Charles Vazquez, Paris, France, assignors to Compagnie Industrielle des Telephones, Paris, France, a corporation of France Application March 28, 1955, Serial No. 497,257

Claims priority, application France April 7, 1954 4 Claims. (Cl. 200-104) The electromechanical relays used in telephone or telegraph exchanges comprise an electro-magnetic motor made up of a fixedmagnetic circuit, one or more coils and one or more movable armatures, and associated with one or more stacks of contact springs on which the relay armatures act. In conventional arrangements, the contact springs are parallel with the largest dimension of the motor, generally the axis of the coil, and placed in such a manner that the front area of the relay is the sum of the apparent area of the motor and that of the stack.

When the relays are mounted in the element racks or bays this arrangement has the advantage of allowing, from the rear of the bays, a wiring on the connection tail pieces of the contact springs, at the same time as a direct accessibility to the contacts at the front of the bays. If it is desired, however, to make relays having a reduced bulk as compared to that of the usual relays, by a general reduction in the dimensions of the component parts of said relays, the followingmain difiiculties are encountered.

In the first place, the small spacing of the springs and the fragility of the tail pieces for soldering, the thickness of which is largely decreased, render difficult the wiring on the relay and render impossible the connection of the relay by plugging into a support due to the small size of the flexible contacts with which said support'has to be provided. In 'thesecond place, the adjustment of the contact springs is made difiicult by the small spacing between springs. In the third place, the efiiciency of the magnetic circuit is largely decreased, which involves increased working powers and'prohibitive heatings of'the coil wires.

The purpose of the present invention is to obviate these drawbacks.

Its object is a small size electro-mechanical relay characterizedin that the stack of contact blades is arranged in line with the control winding of the relay so that the connection tail pieces can be distributed in a regular manner over the entire available frontal area of the relay. The dimensions of these connection tail pieces, their thickness in particular, may be such that they offer the required mechanical rigidity for allowing an easy wiring or a direct plugging in on a support. The contact springs arranged in line with the connection tail pieces on the other side of the stacks are thus suflicientlyspaced for their adjustment to be carried out easily.

Another feature of the relay according to the invention is that the fixed portion of the magnetic circuit or frame of the relay comprises a portion cambered in the plane of symmetry of the relay, acting as a core for the operating winding. The magnetic circuit of the relay comprises another cambered portion, bent in a plane perpendicular to that of the frame and which is used for the articulation of the relay armature. I

This disposition makes it possible, in spite of the small volume provided for thecoil, to have an excellent efficiency of the magnetic circuit, owing to its compact shape with very low magnetic leakages, in the absence of nonmagnetic joints in the fixed portion of said circuit and to the low reluctance of the movable armature.

In such a relay, fixed in its normal position on an element bay, i. c. with the motor disposed towards the front and the stack towardsthe back of the bay, the contact springs are not accessible without displacing the relay with respect to the other elements secured on the bay. Work on the stack, particularly contact adjustment and cleaning should thus be cut down to a minimum. The relay which is an object of the present invention comprises, consequently, contact springs held in blocks made out of strips of moulded insulating material, thereby en-' suring a good stability of the adjustment. It also comprises an arrangement of the contact springs and of their control which is remarkable by the fact that direct mechanical connection between each movable, contact-carrying spring and the armature of the relay is broken as soon as the contact is made. This result is obtained by giving these movable contacts such a camber that they have, of themselves, a tendency to press on a fixed contact blade, so that in the absence of an element for connection with the motor all contacts are closed by their own elastic force.

. The function of the relay motor is to keep open, according to the working or rest condition, one or the other group of these socalled rest or work contacts re tive example, one embodiment of a relay according to the invention. I

Figure 1 shows a view of the relay, in elevation.

Figure 2 is a view of the relay seen from underneath, in Figure l.

Figure 3 is a perspective view, on an enlarged scale of the relay of Figure 1 Figure 4 is an end view of the relay of Figure I seen from the side of the connection tail pieces, and

Figure 5 is an end view of the relay of Figure 1, as seen from the motor side. 1

Referring to the above mentioned figures, it will be seen that the relay comprises a frame 1, made of mild steel, offering at one end a cambered portion 2 and, in the axial plane of the relay, a cambered lug 3 serving as a core for the coil 4, the latter being formed .by a moulded material supporting the winding.

The movable armature comprises a soft iron plate 6 and a stack controlling plate 11, made of insulating inoulded material forced over the arms'12 of the plate 6.

Onthe other side of the plate 11, the plate 6 carries twocambered lugs 7 allowing its articulation on a non-mag-' netic metal plate 8 comprising two wings 9 for holding the plate 8 and secured on theframe 1 by a screw 10 screwing into a tapped hole in the cambered portion 2 of frame 1. i

The motion of the armature 6 is limited, when the relay operates, to the abutment thereof against the core 3 and, when the relay is at rest, by a U-shaped stop 13 secured on the frame 1 by one of its legs by means of an eyelet 14, the other one of its legs coming into contact with the central portion of the plate 11. At the level of i the upper flange 15 of the coil 4, the stop 13. enters a notch of the flange and is provided with two catches which rest against the edges of the notch, thus locking the winding 4 on the core 3.

The construction and arrangement of the stack will be described more especially in connection with Figures 1 and 5, on which the stack may be seen to consist of four blocks 16, 17, 18 and 19 of moulded insulating material, each one of them holding or enclosing three blades of a good conducting metal such as German silver. These blocks 16, 17, 18 and 19 are stacked on top of one an other and are secured firmly to the frame It by tubular eyelets 2% or any other suitable means. The portion of each of the blades outside the relay serves as a connection tail piece, either for soldering or for plugging in, the distribution of the connection tail pieces over the entirety of the front area of the relay thereby facilitating these connections. As regards the inner arrangement of the stack, the blades of the block 16 are used for receiving the outer ends of the windings of the coils not shown in the drawing. To the blades of short length of the block 17, there are secured, by means of electric Welding or any suitable like means, thin German silver contact springs such as the spring 21, split over the entirety of its flexible portion, and provided at its free end with two contact wafers of precious metal. The blades of the block 18, such as 22 are extended inwards with respect to the relay and are provided, at their inner ends, with two precious metal contact wafers opposite the wafers on springs such. as 21. The block 19 is made of a material similar to that of the block 17 and comprises contact springs such as 23. Finally, a return spring 24, made of phosphor bronze, is caught under the attachment eyelets 20 and acts against the ends of the arms 12 of the plate.

The contact springs such as 21 and 23 are so cambered that, if the plate 11 is assumed to be removed, they both apply their contact wafers, against those of the corresponding blade 22 with a predetermined force. The shape of the plate 11 is such that when the relay coil is not energized, the armature 6 is brought back against its rest stop under the action of the spring 24 which is suflicient for moving the springs 23 away from the corresponding blades 22. The springs 21 then rest on the blades 22 and close the rest contacts of the relay' The blades 22, which are very rigid, do not undergo any appreciable displacement under the action of the springs 21. When the relay coil is energized, the electromagnetic force attracts the armature 6, whereupon the plate 11 releases the springs 23 which, owing to their own camber come to press against the blades 22 and close the make contacts of the relay.

The result of this arrangement is that, as soon as a contact spring is applied against the corresponding blade 22, the contact spring is freed of all connections with the movable armature 6, which prevents any contact rebound due to the action thereof, and provided electric contacts with no extraneous vibrations capable of cans ing mechanical or electrical damage thereto. in the second place, the dimensions and camber of the contact springs 21 or 23 are such'that, should a wear of the contacts occur, though strongly decreased as set forth above, the force of application of said springs on the blades 22 remains practically unchanged. Finally, the operating current of the relay, determined by the resultant force of the opposite stresses of the springs 23 and of the spring 24 may be adjusted by acting on the spring 24 alone, without acting on the springs 23.

The tapped hole 25 provided in the frame 1 is intended for receiving a screw for attaching the relay.

Numerous modifications of the relay according to the invention particularly as regards the shapes and materials of the component parts, as well as the number and arrangement of the blades and contact springs, may be ob tained within the scope of the invention.

What is claimed is:

1. An electromagnetic relay comprising a magnetic circuit formed by a frame provided at one end thereof with a bent portion and with an essentially rectilinear portion, a movable armature supported at one side thereof by said bent end portion of the frame to enable articulate movement of said armature about an axis adjacent said one side, a stack of contact springs having free ends and disposed essentially parallel to said rectilinear portion and directed toward said bent portion of the frame, a magnetic core with at least one winding thereon with the axis thereof essentially perpendicular to said rectilinear portion and disposed between said bent portion and the free ends of said contact springs, the other side of said armature opposite said one side adjacent said articulation axis being provided with a central recess thereby leaving on both sides thereof narrow armature portions, an essentially flat return spring disposed above said contact springs and secured to said stack, said contact springs consisting of a plurality of groups of contact springs disposed alongside one another, an insulating stack controlling plate for the movable contact blades forced over said narrow armature portions to such an extent as to leave a certain amount of the free ends of said narrow armature portions protrude therebeyond, the free end of said return spring being in direct contact with the protruding ends of said narrow movable armature portions and thereby forming an assembly constituting one face of the relay while the opposite face of the relay is formed entirely by said rectilinear portion of the magnetic circuit, and a stop member for said movable armature fixed to said frame and located on the same side as said magnetic core with respect to the articulation axis of said armature, said stop mem ber including an elbow portion the outer end of which determines the normal rest position of said movable armature, said stop member passing through an aperture limited, on the one hand, by the said recess at the end of said movable armature and, on the other, by the insulating stack controlling plate and providing a support by the inner face of said elbow portion for the upper face of said insulating stack controlling plate when the latter together with said movable armature is urged against said stop member by said return spring in the absence of an energizing current in said winding.

2. An electromagnetic relay according to claim 1, wherein said stack of contact springs comprises one relatively fixed blade disposed between two movable blades and supported by block means of molded material, said two movable blades each having a camber of such shape as to normally tend to apply themselves against said fixed center blade, each of said movable blades being formed in two parts, one part thereof forming the connecting piece and held by the molded material of said block means and the other part forming a contact spring secured to said first part, the contact springs being essentially flat over the entire length thereof.

3. An electro-magnetic relay according to claim 2,

wherein said other part of said movable blades is secured to said one part thereof by electric welding after molding of said block means.

4. An electromagnetic relay comprising a magnetic circuit formed by a frame provided at one end thereof with a bent portion and with an essentially rectilinear portion, a movable armature supported at oneside thereof by said bent end portion of the frame to enable articulate movement of said armature about an axis adjacent said one side, a staclt of contact springs having free ends and disposed essentially parallel to said rectilinear portion and directed toward said bent portion of the frame, a magnetic core with at least one winding thereon with the axis thereof essentially perpendicular to said rectilinear portion and disposed between said bent portion and the free ends of said contact springs, the other side of said armature opposite said one side adjacent said articulation axis being provided with a central recess thereby leaving on both sides thereof narrow armature portions, an essentially fiat return spring disposed above said contact springs a 5 and secured to said stack, said contact springs consisting of a plurality of groups of contact springs disposed alongside one another, an insulating stack controlling plate for the movable contact blades forced over said narrow armature portions to such an extent as to leave a certain amount of the free ends of said narrow armature portions protrude therebeyond, the free end of said return spring being in direct contact with the protruding ends of said narrow movable armature portions and thereby forming an assembly constituting one face of the relay while the opposite face of the relay is formed entirely by said rectilinear portion of the magnetic circuit, said stack of contact springs comprising one relatively fixed blade disposed between two movable blades and supported by block means of molded material, said two movable blades each having a camber of such shape as to normally tend to apply themselves against said fixed center blade, each of said movable blades being formed in two parts, one part' forming a contact spring secured to said first part, the

contact springs being essentially flat over the entire length thereof.

References Cited in the file of this patent UNITED STATES PATENTS I r 1,815,947 Lewis July 28, 1931 1,981,259 Wertz Nov. 20, 1934 2,355,047 Bennett Aug. 8, 1944 2,369,616 Spahn Feb. 13, 1945 2,524,874 Bean Oct. 10, 1950 2,591,684 Deakin Apr. 8, 1952 FOREIGN PATENTS 130,190 Australia Nov.-23, 1948 267,799

Switzerland July 1, 1950 

